Transfer Device for Mail Items

ABSTRACT

A transfer device for mail items with a transfer unit which has an ejection point for transferring individualized mail items to an item carrier is provided. Further, the transfer device includes a transport device for transporting the mail items to the ejection point in a direction of transport. The transport device includes two belts for holding the mail items on both sides and for transporting the mail items and further has means for adapting a space between the belts to the thickness of a mail item. The means for adapting is a belt tilt means which is pivotal about an axis of rotation, the pivotal movement pivoting one of the belts and therefore a distance between the belts is variable.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of German Patent Application No. 102008 034 179.7 DE filed Jul. 22, 2008, which is incorporated byreference herein in its entirety.

FIELD OF INVENTION

The invention relates to a transfer device for mail items, having atransfer unit which has an ejection point for transferring theindividualized mail items to an item carrier and a transport device fortransporting the mail items to the ejection point in a direction oftransport, which includes two belts, for holding the mail items on bothsides and transporting them, and a means for adapting the spacingbetween the belts to the thickness of a mail item.

BACKGROUND OF INVENTION

Mail items, such as letters, large letters, postcards, wrapped journals,flat packets and the like, are sorted by their address in mail centersor large post offices in very large numbers and are deposited in aplurality of containers. For this, DE 10 2005 059 601 B3 discloses asorting installation in which the mail items are transported, standingupright on their longitudinal edge, in a direction of transport to aring of pigeonholes moving past transversely to the direction oftransport. The mail items are shot one after the other into thepigeonholes, which move past horizontally, with the high cycle rate andthe high density of the stream of items supplied having the effect thata very small time window is available each time for shooting a mail iteminto a pigeonhole as it moves past.

To increase the size of this time window somewhat, the stream of itemsis transported to the pigeonhole ring in a loading arm, it beingpossible for the ejection point thereof at which the mail items aretransferred from the loading arm to the individual pigeonholes to beentrained horizontally with the moving pigeonholes. Once a mail item hasbeen shot into a pigeonhole the loading arm is retracted and theejection point aligned with a succeeding pigeonhole.

SUMMARY OF INVENTION

It is an object of the present invention to provide a transfer device bymeans of which mail items of differing thickness can be reliablytransferred to moving pigeonholes of an item carrier.

This object is achieved by a transfer device of the type mentioned inthe introduction, in which the means for adapting the spacing betweenthe belts is a belt tilt means which is pivotal about an axis ofrotation and whereof the pivotal movement pivots one of the belts and somakes its distance from the other belt variable. It is a simple matterto press in controlled manner against the belt tilt means, thiscontrolled contact pressure being a crucial parameter for achievingsatisfactory quality of transport of the mail items through thetransport device with at most a low level of slip.

Adapting the spacing between the belts to the thickness of a mail itemwhich is currently being transported may be achieved by adjusting thepivot angle from the outside, for example using a processing means, or aself-adjustment mechanism of the belt tilt means. The belt tilt meansmay have a deflection roller, preferably directly at the ejection point,which deflects the pivotal belt, in particular at the outermost positionof the belt—that is to say where the belt is guided the furthest towardthe item carrier. The deflection roller may, together with the deflectedbelt, be pivotal about the axis of rotation of the belt tilt meansarranged outside the deflection roller. The ejection point may be alocation on the transfer unit at which the mail items leave the transferunit, for example by way of a chute or to guided transfer to theadjacent item carrier. The belts are preferably motorized endless belts.For further guidance of the mail items, the transfer unit may have anadditional underlying belt on which the mail items stand on theirlongitudinal edge as they are transported by the two belts. The mailitems may be mailings of all kinds. The item carrier may take the formof a pigeonhole ring with revolving pigeonholes.

So that the ejection point can be entrained in a manner adapted tomovement of the item carrier, the transfer unit advantageously includesan entraining drive which is controlled by a processing means. Theejection point may be entrained, temporarily synchronized with amovement of the item carrier which is in particular transverse inrelation to the direction of transport, where “transverse” is understoodbelow to mean an angle of between 70° and 110°. After a synchronizedentrainment of this kind, the transfer unit can be pivoted back, withthe high cycle rate of the transported mail items making it possible fora high moment of acceleration to act on the transfer unit and hence alsoon the entrained belt tilt means.

The transport device should be capable of transporting mail items of thegreatest variety of thicknesses in a manner at least substantially freeof slip even under considerable lateral acceleration, in particular ofup to 6 g. To this end, in a preferred embodiment of the invention, thebelt tilt means includes a compensation means which, in the event ofacceleration of the ejection point both in the direction of and inopposition to a movement of the item carrier, acts to counter anyclosing or opening of the belts caused by inertia. By compensating fullyor at least to a large extent for any movement of the belt tilt meansand hence one of the belts caused by inertia, it is possible to preventthe belts from closing or opening—that is to say moving toward oneanother or away from one another—if the transfer unit is forcefullyaccelerated. Depending on the construction of the compensation means ortransfer unit, any relationship between closing and opening and thedirection of acceleration is possible.

The compensation means may be electronically controlled orself-regulating, for example with the aid of a sensor. A particularlysimple and reliable means is a counterweight which acts to counter anymovement of inertia by the other components of the belt tilt means as aresult of its own inertia. The counterweight may be a counterweight tothe mass of the belt tilt means on the ejection side, and be mountedopposite the ejection point in relation to the axis of rotation.Advantageously, it is connected to the ejection point with the aid of arigid arm, with the result that dynamic movements are kept small.

The belt tilt means is advantageously arranged with its axis of rotationsuch that any movement of the belt tilt means caused by acceleration inthe direction of acceleration of the ejection point is fully or partlycompensated in the direction transverse to the direction of transport.The transfer unit, which may take the form of a loading arm, may bemoved transverse to the direction of transport without any disadvantage,as a result of which a considerable degree of freedom of movement inrelation to the item carrier can be achieved.

Particularly good compensation of movements of the belt tilt meanscaused by acceleration can be achieved if the center of gravity of thebelt tilt means lies on the axis of rotation.

To keep transport of a mail item between the belts as free of slip aspossible, the two belts have to be pressed toward one another and towardthe mail item by a contact pressure force so that the mail item is heldsecurely between them. This contact pressure force may be applied by oneor more spring elements. The occurrence of wear associated with thecontact pressure force may be countered if the form of the belt run ofthe belt of the belt tilt means gives rise to the contact pressure forceon the belt tilt means. The belt run of the belt of the belt tilt meansis advantageously formed such that the resultants of the force of thebelt gear form a force component which imparts a moment of contactpressure to the belt tilt means. To this end, a tension force of one ofthe belts, in particular the belt associated with the belt tilt means,may exert a closing force on the belt tilt means. An additional contactpressure on the tilt means may be applied by a spring construction.

Rarely, and for a vast variety of reasons, it may occur that propertransfer of a mail item from the transport device to the item carrierdoes not proceed smoothly and the mail item remains stuck in the regionof the ejection point, between the item carrier and the transfer unit.As a result of continued movement by the item carrier, which it may notbe possible to stop abruptly because of its weight, the mail item ispulled further and may possibly pull the entire transfer unit with it,with the result that there is a risk of damage to the mail item and thetransfer unit. To prevent this, the transfer device advantageouslyincludes a release means for opening the belt tilt means wide enough fora mail item between the belts to be released at the ejection point. Themail item may be transported further by the item carrier without thetransfer unit being pulled with it. When the belt tilt means is openedat the ejection point, the belts are advantageously spaced from oneanother by at least 10 cm.

When the belt tilt means is opened, the contact pressure force providedfor holding the mail item in the transport device has to be overcome. Sothat this act of overcoming the pressure is not left to the mail item,the release means advantageously has a gear for opening the belt tiltmeans to such an extent that a mail item is fully released in a regionextending from the ejection point by at least 30 cm in opposition to thedirection of transport, in a direction of acceleration of the ejectionpoint. The direction of acceleration is advantageously the direction oftransport of the item carrier. The transfer unit and the ejection pointthereof may be accelerated, for example in order to position theejection point at a succeeding pigeonhole of the item carrier, without amail item that is jammed in the item carrier striking against the belttilt means.

Advantageously, the opening is wide enough for it to be possible to movethe mail item by a distance of at least 50 cm in the direction ofacceleration without coming into contact with the belt tilt means.

Advantageously, the release means includes a motorized drive for openingthe belt tilt means. A considerable force can be introduced at highspeed and the belt tilt means can be particularly rapidly and widelyopened.

To ensure rapid introduction of force to the belt tilt means, duringopening advantageously the release means is connected to the belt tiltmeans without the use of a spring, with the result that the belt tiltmeans is opened without the use of a spring. To make a certain springaction of the belt tilt means still possible when the belt tilt means isin normal operation, advantageously the belt tilt means is pivotalsomewhat in a spring means when the release means is at rest, inparticular at a point where the release means acts on the belt tiltmeans. A spring contact pressure can have the effect that opening of thebelt tilt means is resisted, in opposition to the spring contactpressure, in the first phase of jamming of a mail item, until the belttilt means is opened beyond the initial deflection angle by actuator.

Advantageously, the belt tilt means includes a spring element forpressing the belts toward one another, for example to aid a contactpressure by the belts. Should the belt tilt means be opened by a safetyfunction, the direction of this opening movement is in opposition to thespring pressure, with the result that in some cases the contact pressureis in opposition to the spring force and hence becomes more difficult.To avoid this, the spring advantageously acts on the transfer unit suchthat an opening movement of the release means has the effect of relaxingthe spring. This can help the belt tilt means to open for the purpose ofthe safety function.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail by means of an exemplaryembodiment, which is illustrated in the drawings.

In the drawings:

FIG. 1 shows a transfer device having a movable transfer unit, in adiagrammatic plan view,

FIG. 2 shows the transfer unit in a more detailed plan view, and

FIG. 3 shows the transfer unit from FIG. 2, with a belt tilt means fullyopen.

DETAILED DESCRIPTION OF INVENTION

FIG. 1 shows a transfer device 2 in a diagrammatic plan view. Itincludes a transfer unit 4 in the form of a loading arm which ismovable, in particular pivotal, in relation to a stationary unit 6. Themobility is indicated by a broken line in which the transfer unit 4 isindicated pivoted by 6° in relation to a starting position. In itsstarting position, mail items 8 are transported by a transport device 10which has two revolving belts 12, 14, in a straight line in thedirection of transport 16 from the stationary unit 6 to the loading armor transfer unit 4. Depending on the angle of pivoting of the loadingarm, the path of transport is angled somewhat in the region between thestationary unit 6 and the loading arm.

At a small spacing from the transfer unit 4, there is arranged an itemcarrier 18 in the form of a pigeonhole ring which includes a pluralityof pigeonholes or item containers 20 that are arranged one behind theother, in the form of a train, and are secured such that they aremovable in relation to one another. When the transfer device 2 is inoperation, the item carrier 18 moves in a carrier direction 22, whichextends perpendicular to the transport direction 16 when the transferunit 4 is untilted. Mail items 8 that are transported in the transferunit 4 are shot one after the other into a respective pigeonhole 20,with the frontmost end of the transfer unit 4 being entrained in amanner synchronized in speed and position with the respective itemcontainer 20 into which the next mail item 8 is to be inserted.

When a mail item 8 is transferred from the transfer unit 4 to the itemcarrier 18, the mail item 8 leaves the transfer unit 4 at an ejectionpoint 24 that is formed by the frontmost elements of the transfer unit4. These elements may for example be two rollers 26, 28 with the twobelts 12, 14. Once the mail item 8 is deposited fully in the desireditem container 20, the transfer unit 4 is pivoted back somewhat in theclockwise direction until the ejection point 24 is positioned opposite asucceeding item container 20, so that a mail item 8 can be inserted intothe latter.

The mail items 8 are transported in the direction of transport 16 by thetransport device 10, at a speed of 2.5 m/s, and are inserted into theitem containers 20, which move at a speed of 0.5 m/s perpendicular tothe direction of transport 16. Between the individual mail items 8 thereare small gaps which make it possible to align the transfer unit 4 inits new position in front of a succeeding item container 20. Thisre-positioning is carried out at a frequency of approximately 3 Hz.Here, in particular the front part of the transfer unit 4, together withthe ejection point 24, is accelerated powerfully in a direction ofacceleration that is substantially parallel or antiparallel to thecarrier direction 22.

So that transport of mail items 8 of differing thickness is possiblebetween the belts 12, 14 and in particular between the rollers 26, 28,the roller 26 and with it the front part of the belt 14 are mounted tobe movable in relation to the roller 28 and the belt 12. When thetransfer unit 4 is accelerated, forces of inertia act on the movablemounting, the roller 26 and the front part of the belt 14, as a resultof which a contact pressure force of the belt 14 exerted on the mailitem 8 that is currently being transported would vary were it not for acorresponding counter-action. This would result in too strong or tooweak a contact pressure and hence in damage to the item or slipping ofthe mail item 8 between the belts 12, 14.

To prevent this, the front roller 26 is part of a belt tilt means 32, bymeans of which part of the belt 14 is mounted to be pivotal about anaxis of rotation 34. The front roller 26 is secured to a rigid tilt arm36, which is mounted on the axis of rotation 34 and carries acounterweight 38 at its end in opposition to the roller 26. Thedistribution of mass of the belt tilt means 32 is in this case set suchthat its center of gravity comes to lie on the axis of rotation 34.

In the event of the transfer unit 4 moving pivotally about its axis ofrotation 30 and acceleration in or in opposition to the pivotalmovement, the belt tilt means 32 is dynamically counterbalanced thereby,with the result that the forces of inertia of the individual elements ofthe belt tilt means 32 counteract one another and the belt tilt means 32remains at rest even if there is considerable acceleration in relationto the other parts of the transfer unit 4, for example the roller 28.This means that a contact pressure force which presses the belt tiltmeans 32 and with it the belt 14 in the direction of the belt 12 remainsat least substantially unaffected by the acceleration.

A contact force pressing the belt tilt means 32 in the direction of thebelt 12 is created by an advantageous form of the belt run of the belt14. The belt 14 is tensioned at a force of approximately 300 N. Thisforce pulls the front roller 26 backward as indicated by the arrow 40.The direction of the arrow 40 is the direction of the bisector of theangle formed by the belt 14 as it is deflected by the roller 26. Thealignment of the tilt arm 36, that is to say the direction of the linebetween the axis of rotation 34 and the axis of rotation of the roller26, is selected such that an angle is produced between the tilt arm 36,or the line connecting the axes of rotation, and the force resultantindicated by the arrow 40. Because the line connecting the axes ofrotation does not coincide with the force resultant, a torque is exertedon the belt tilt means 32, in the direction of the force resultant. Thistorque has the effect of exerting a contact pressure force on the belttilt means 32, in the direction of the belt 12. The contact pressureforce is for example between 10 and 20 N, depending on the angularposition of the belt tilt means 32. This depends on the thickness of themail item 8 that is currently being transported between the belts 12,14. Closing of the belt tilt means 32, brought about by the contactpressure force, and hence clamping of the mail item 8 between the belts12, 14, may be further reinforced by a spring element.

Arranged in the region of the axis of rotation 34 is a roller 42 whichdeflects the belt 14 and whereof the axis of rotation is the axis ofrotation 34. As a result of this, the path of the belt 14 between therollers 26, 42 remains the same regardless of the angular position ofthe belt tilt means 32. As a result of the angle between the tilt arm 36and the direction of transport 16, when the belt tilt means 32 closes,however, the spacing between the front roller 26 and a rear roller (notillustrated) or the axis of rotation 30 becomes smaller. This means thatthe tension force of the belt 14 is reduced somewhat when the belt tiltmeans 32 closes, which has the effect of reducing the tension force ofthe belt 14 and hence the contact pressure force or closing force of thebelt tilt means 32. This is countered by an increase in the anglebetween the force resultant (represented by the arrow 40) and the tiltarm 36 when the belt tilt means 32 closes, which reinforces a contactpressure force or closing force of the belt tilt means 32. Depending onthe direction of the angle or the elasticity of the belt 14, these twomutually opposing effects can be balanced so that the closing force isindependent of the closing angle of the belt tilt means 32 or can beadjusted to another advantageous form.

FIG. 2 shows the transfer unit 4 in a more detailed view from above. Thebelt tilt means 32 is illustrated with its tilt arm 36, thecounterweight 38, its roller 26 at the ejection point 24 and its contactpressure belt 14. Also illustrated is a release means 44 with amotorized drive 46 and a gear 48 that is connected at a point of action50 to a mounting 52 on which the tilt arm 36 is secured.

The tilt arm 36 may be pivoted slightly in relation to the mounting 52,as indicated at a pin 54 in a slot 56. When the drive 46 is at rest, themounting 52 is mounted rigidly in relation to the drive 46, it beingpossible for the tilt arm 36 to pivot somewhat in order to adapt itsopen position to mail items 8 of differing thickness. With the aid of aspring 58, which is visible in FIG. 3, the belt tilt means 32 is pressedin the direction of its closed position, in its position illustrated inFIG. 2.

FIG. 3 shows the transfer unit 4 with the belt tilt means 32 fully open.In this position, the belt tilt means 32 is turned by more than 90°relative to the position shown closed in FIG. 2, with the contactpressure belt 14 pivoted by 90° in its region facing the mail item 8relative to its closed position shown in FIG. 2. The spring 58 that isillustrated in FIG. 3 takes the form of a torsion spring and is wound ina spiral about the axis of rotation 34, with the end of the spring 58that projects to the left and is visible in FIG. 3 being illustrated aspointing to the left only for the sake of the illustration to make thespring visible. In a correct illustration, the end illustrated would besecured below a mounting 60 and not visible in plan view.

FIG. 3 shows the belt tilt means 32 with the safety function actuated.The front end of a mail item 8 has left the ejection point 24 and haspartly entered the interior 62 of an item container 20. There the mailitem 8 has for example jammed, with the result that it is not insertedany further into the interior 62 despite a feed force effected by thebelts 12, 14, which acts in the direction of the ejection point 24 andhence into the item container 20. In the meantime, the entire itemcarrier 18 has moved on in the carrier direction 22, entraining theejection point 24 in synchronized manner, with the result that there isno or only a small relative movement between the interior 62 and theejection point 24.

With the aid of a sensor 64, for example an optical sensor 64, the gapbetween the ejection point 24 and the item carrier 18 is scanned, thesensor 64 being connected to a processing means 66 and the processingmeans 66 monitoring the gap and hence the insertion of the mail item 8into the interior 62. The processing means 66 recognizes that the forexample optical measuring beam generated by the sensor 64 is stillinterrupted, so the mail item 8 has not yet been fully inserted into therelevant item container 20.

At a later point in time, the transfer unit 4 reaches a position inwhich synchronized entrainment with the item carrier 18 is normallystopped. This would have the effect that the front end of the mail item8 would be transported further in the carrier direction 22, while theejection point 24 is at rest or is even guided back in the opposingdirection. To prevent damage caused in this way to the mail item 8 andthe transfer unit 4, the processing means 66 triggers the drive 46, withthe result that the latter moves the gear 48 as indicated by an arrow68. The gear 48 acts on the mounting 52, which is form-fittinglyconnected to the tilt arm 36 and pulls the latter into its openposition, which is shown in FIG. 3. The belt tilt means 32 is nowopened, by the angle of opening 70 in relation to the closed position.

The mail item 8, which is for example 35 cm long, is fully released bythis and can now be guided further in the carrier direction 22 withoutcoming into contact with the contact pressure belt 14 or another elementof the belt tilt means 32 or the transfer unit 4. This drasticallyreduces the risk of damage to the mail item 8 or the transfer unit 4.There is now enough time to stop the item carrier 18 and to remove thebacklog of items without affecting elements of the transfer device 2.

When the belt tilt means 32 is opened to its open position, asillustrated in FIG. 3, the gear 48 moves the tilt arm 36 in oppositionto the spring force of the spring 58, which is tensioned more as theangle of opening 70 increases. In another embodiment, the spring 58,which is provided to apply a contact pressure force of the belt tiltmeans 32 to the mail item 8 that is being transported between the belts12, 14, may be applied by another or an alternative spring 72 which inFIG. 3 is shown diagrammatically in the form of a square between thetilt arm 36 and the mounting 52. The spring 72 presses the tilt arm 36away from the mounting 52, with the result that in the closed positionof the belt tilt means 32 a contact pressure force is exerted on themail item 8 between the belts 12, 14 by way of the tilt arm 36 and thecontact pressure belt 14.

When the drive 46 is actuated to open the belt tilt means 32, themounting 52 can turn counter-clockwise somewhat without the form-fittingconnection acting on the tilt arm 36. This turning initially relaxes thespring 72, with the result that the mutual contact pressure force on thetwo belts 12, 14 is reduced. During this, the spring 72 moreover helpsto actuate the gear 48, since it urges in the direction of its openposition. As the mounting 52 is pivoted further, the form-fittingconnection acts between the mounting 52 and the tilt arm 36, with theresult that the tilt arm 36 is pulled into its open position. Duringthis the spring 72 can remain pre-tensioned somewhat so that the tiltarm 36 is guided without play.

1.-11. (canceled)
 12. A transfer device for mail items, comprising: atransfer unit including an ejection point for transferring the mailitems to an item carrier; a transport device for transporting the mailitems to the ejection point in a direction of transport, the transportdevice including two belts for holding the mail items on two sides andfor transporting the mail items; and a belt tilt device for adapting aspace between the two belts to the thickness of a mail item, the belttilt device being pivotal about an axis of rotation, wherein a pivotalmovement pivots one of the belts resulting in that a distance betweenthe two belts is variable.
 13. The transfer device as claimed in claim12, wherein the belt tilt device includes a compensation acting tocounter any closing or opening of the belts caused by inertia in case ofan acceleration of the ejection point both in a direction of and inopposition to a movement of the item carrier.
 14. The transfer device asclaimed in claim 13, wherein the compensation is a counterweight. 15.The transfer device as claimed in claim 13, wherein the direction ofacceleration of the ejection point is transverse to the direction oftransport.
 16. The transfer device as claimed in claim 14, wherein thedirection of acceleration of the ejection point is transverse to thedirection of transport.
 17. The transfer device as claimed in claim 12,wherein a center of gravity of the belt tilt device lies on the axis ofrotation.
 18. The transfer device as claimed in claim 12, wherein atension force of one of the belts exerts a closing force on the belttilt device.
 19. The transfer device as claimed in claim 12, furthercomprising: a release device for opening the belt tilt device wideenough for a mail item between the belts to be released at the ejectionpoint.
 20. The transfer device as claimed in claim 19, wherein therelease device has a gear for opening the belt tilt device to such anextent that a mail item is fully released in a region extending from theejection point by at least 30 cm in opposition to the direction oftransport and in a direction of the acceleration of the ejection point.21. The transfer device as claimed in claim 19, wherein the releasedevice includes a motorized drive for opening the belt tilt device. 22.The transfer device as claimed in claim 20, wherein the release deviceincludes a motorized drive for opening the belt tilt device.
 23. Thetransfer device as claimed in claim 19, wherein the belt tilt device ispivotal in a spring means at a point where the release device acts onthe belt tilt device.
 24. The transfer device as claimed in claim 20,wherein the belt tilt device is pivotal in a spring means at a pointwhere the release device acts on the belt tilt device.
 25. The transferdevice as claimed in claim 21, wherein the belt tilt device is pivotalin a spring means at a point where the release device acts on the belttilt device.
 26. The transfer device as claimed in claim 12, furthercomprising: a spring for pressing the belts toward one another, duringwhich an opening movement of the release device has the effect ofrelaxing the spring.
 27. The transfer device as claimed in claim 19,further comprising: a spring for pressing the belts toward one another,during which an opening movement of the release device has the effect ofrelaxing the spring.